1,167 research outputs found
Multiscale mathematical models for simulation and scale-up of green processes in the perspective of industrial sustainability
The present work presents research studies aimed at developing tools useful to design
engineering solutions moving in the direction of industrial sustainability. The investigations
hereinafter discussed regard an extraction process of active compounds \u2013 polyphenols \u2013 from
agro-food industry wastes (olive and grape pomaces) and a biorefinery exploiting waste
frying oil, solid organic wastes and algal biomass to produce biofuels. In particular, for the
former topic, a procedure aimed at the evaluation of the technological feasibility at pilot scale
of said process is discussed. The proposed approach takes into consideration the extended
kinetic route coupled with mathematical simulation. Detailed physically-based dynamic
mathematical models, taking into account mass and energy balance equations, are adopted
to describe both the lab-scale and the pilot-scale reactors. Chemical physical parameters
appearing in the models are estimated from the experimental data at lab-scale or are partially
taken from literature. Different heating systems are designed for the pilot scale reactor and
their performance is tested by simulation. Characteristic times are evaluated also during
start-ups and different control loops are analyzed in order to set-up the best process and
operating variables. Average yields in polyphenols are finally evaluated for both the batch
and the continuous operated pilot reactor, by considering feed variability and fluctuations of
process parameters.
For what concerns the biorefinery, special attention was devoted to the modeling of the
airlift reactor, its most delicate and complex component. In fact, to optimize this interesting
microalgae cultivation system, a precise description of the moving interfaces formed by the
liquid and gas phase is critical. In this study, coupled front capturing methods (standard and
conservative level set methods) and finite difference method are used to simulate gas bubbles
dynamics in a pilot-scale external loop air-lift photobioreactor in which microalgae are used
to capture CO2 from flue gas and to treat wastewater. Numerical simulations are carried out
on rectangular domains representing different sections of the vertical axis of the riser. The
data employed was either acquired from previous experimental campaigns carried out in the
airlift reactor or found in the literature. The rise, shape dynamics and coalescence process of
the bubbles of flue gas are studied.
Moreover, for each analyzed applications, a procedure based on Buckingham \u3c0-theorem
to perform a rigorous scale-up is proposed. In this way, scale-invariant dimensionless
groups describing and summarizing the considered processes could be identified. For the
research focused on the scale-up of photobioreactors used to cultivate Chlorella Vulgaris,
an experimental campaign at three levels was designed and carried out to evaluate the
characteristic dimensionless numbers individuated by the theoretical formulation. Since
scale-up regards both geometrical dimensions and type of reactor, passing from lab-scale
stirred tanks to pilot scale tubular and airlift, particular attention was devoted to define
characteristic lengths inside the dimensionless numbers
Elucidating the role of the tumor suppressor Protein Phoshatase 2A in Chronic Myeloid Leukemia.
Protein phosphatase-2A (PP2A) is one of the major cellular serine-threonine
phosphatases and is involved in the regulation of cell homeostasis through the
negative regulation of signaling pathways initiated by protein kinases. As several
cancers are characterized by the aberrant activity of oncogenic kinases, it was not
surprising that a phosphatase like PP2A has progressively been considered as a
potential tumor suppressor. Indeed, multiple solid tumors (e.g. melanomas,
colorectal carcinomas, lung and breast cancers) present with genetic and/ or
functional inactivation of different PP2A subunits and, therefore, loss of PP2A
phosphatase activity towards certain substrates. Likewise, impaired PP2A
phosphatase activity has been linked to B-cell chronic lymphocytic leukemia,
Philadelphia-chromosome positive acute lymphoblastic leukemia and blast crisis
chronic myeloid leukemia (CML). In CML the deregulated tyrosine kinase activity of
p210-BCR/ABL oncoproteins is sufficient to induce and sustain the leukemic
phenotype, and contributes to disease progression. Imatinib mesylate, a BCR/ABL
kinase inhibitor, is effective in most of chronic phase CML patients. However, a
significant percentage of CML patients develop resistance to imatinib and/or still
progresses to blast crisis, a disease stage that is often refractory to imatinib
therapy. Furthermore, there is compelling evidence indicating that the CML
leukemia stem cell is also resistant to imatinib. We have recently reported that the
phosphatase activity of PP2A is markedly inhibited in blast crisis and, to a lesser
extent, chronic phase CML patient cells and that pharmacologic re-activation of
PP2A phosphatase activity by activating drugs such as Forskolin and FTY720 led
to growth suppression, enhanced apoptosis impaired clonogenic potential and
decreased in vivo leukemogenesis of imatinib-sensitive and
-resistant CML-BC and CML-CP patient. Furthermore we have evidence that PP2A
inactivation is an event that occurs also at the level of the leukemic stem cell and
that PP2A re-activation hampers the survival and self-renewal of CML stem cells
and possibly overcome the resistance of CML quiescent stem cells to tyrosine
kinase inhibitor monotherapy. Thus, inducing PP2A phosphatase activity has the
potential to eradicate CML by efficiently targeting both leukemic stem and
progenitor cells regardless of their degree of sensitivity to kinase. Therefore, the
combination of PP2A phosphatase-activating and BCR/ABL kinase-inhibiting drugs
may represent a powerful therapeutic strategy for CML patients
A level set approach for computation of bubble dynamics in airlift reactors.
In this work, we employ the so-called level set approach to simulate the rising of gas bubbles in a pilot-scale external loop airlift photobioreactor in which microalgae are used to capture CO2from flue gas and to treat wastewater. A coupled level set and finite difference method is adopted in this work to track the moving gas-liquid interfaces in the ALR riser. Level set methods implicitly represent dynamic fronts by solving an Hamilton-Jacobi partial differential equation such as the normal flow equation, in turn dependent on a flow function that can be regarded as a speed vector field. This latter, for the case at hand, is obtained by solving the non-dimensional Navier-Stokes equations through a Chorin type projection technique on a staggered gri
Assembling defenses against therapy-resistant leukemic stem cells: Bcl6 joins the ranks
The resistance of leukemic stem cells in response to targeted therapies such as tyrosine kinase inhibitors (TKIs) relies on the cooperative activity of multiple signaling pathways and molecules, including TGFβ, AKT, and FOXO transcription factors (TFs). B cell lymphoma 6 (BCL6) is a transcriptional repressor whose translocation or mutation is associated with diffuse large BCL. New data now show that BCL6 is critical for the maintenance of leukemias driven by the BCR-ABL translocation (Philadelphia chromosome), suggesting that BCL6 is a novel, targetable member of the complex signaling pathways critical for leukemic stem cell survival
A Low-Cost Monitoring System and Operating Database for Quality Control in Small Food Processing Industry
The use of completely automated systems for collecting sensor data with the aim of monitoring and controlling the quality of small-scale food processes is not widespread. Small and micro-enterprises usually do not carry out their own precompetitive research or prototype development as regards to automation technologies. This study proposes a web-based, low-cost monitoring and supervisory control and data acquisition (SCADA) system whose kernel is available for free, as a possible solution that could be adopted by these food producers. It is mainly based on open SW/HW so as its configuration is adaptable to the application and type of plant. It presents a modular architecture and its main functionalities encompass the acquisition, management, aggregation and visualization of process data, providing an operating database. It also provides food tracking and process quality control: The time series are browsable due to QR-Code generation and different early warning detection strategies are implemented. A tool for solving migration problems based on Fick\u2019s equation is offered as a packaging decision support system
Novel insights on pink discoloration in cheese: The case of Pecorino Toscano
Pink discoloration in cheese has been the subject of wide research, but the basis for this phenomenon remains elusive. This defect impacts a wide range of ripened cheeses, resulting in the rejection of cheese and a consequent economic loss for dairy industries. As multiple causes for pink discoloration have been reported for different cheeses in the literature, the aim of this research was to investigate the cause of a pink discoloration found on Pecorino Toscano cheese rind. The results of microbiological analysis revealed the presence of high microbial counts associated to the rind and the nearest inner part. Strains isolated from the coloured part were mainly identified as Serratia liquefaciens, suggesting that an environmental contamination of the cheese rind by this species could be the cause of the observed defect and expanding the knowledge related to pink discoloration in cheeses
Arthrospira platensis Extract: A Non-Invasive Strategy to Obtain Adjunct Attenuated Cultures
This study aims at proposing the use of Arthrospira platensis, commonly known as Spirulina, extract as a non-invasive method to attenuate the growth rate of non-starter adjunct cultures, thus preventing the over-acidification that may occur during cheese manufacturing. A preliminary screening using four different concentrations (0.20%, 0.30%, 0.50%, and 0.70%) of A. platensis extract and four starter and three non-starter lactic acid bacteria strains was performed by impedometric analysis. This allowed us to select one starter and one non-starter strain to be used in the in vitro simulation of a co-culture in milk with the best antimicrobial concentration (0.3%). The growth dynamics of the two selected strains, starter Lactococcus lactis 1426 and non-sarter Lacticaseibacillus rhamnosus 1473, co-cultured for 120 h was monitored by three different approaches: (i) plate counting on M17, for the enumeration of lactococci, and MRS for lactobacilli; (ii) fluorescence microscopic counting of viable and non-viable coccoid Lactococcus lactis 1426 and rod-shaped Lacticaseibacillus rhamnosus 1473 cells; (iii) the overall estimation of co-culture growth behavior by impedometric parameters Lag, Rate, and yEnd. All the data obtained from the in vitro simulation were in agreement, revealing that a slowdown of non-starter growth occurred, while the starter strain was not affected, or slightly stimulated, from the antimicrobial presence. In particular, the growth of Lb. rhamnosus 1473 was delayed without adversely compromise the cells’ integrity, connected with metabolic functions, showing a great potential for use in cheese production
Adhesion of sea-urchin living cells on nano-patterned anodic porous alumina
In this work we investigated the possibility of using living cells as stress sensing material in biosensors, in the light of the three Rs principle \u2013 Replacement, Reduction and Refinement . This approach requires the necessity to cultivate them on biocompatible electrical conducting substrate and to insert the circuit into a culture chamber that must assure both the transport of oxygen and the diffusion of the medium containing the potential stressor to the cells, without modifying their response and the structure of the culture. To this aim we fabricated nano-patterned substrates of anodic porous alumina to be used for enhancing cell adhesion, and culture chambers made in polylactic acid. Sea-urchin cells (coelomocytes) were cultured on these substrates at different times of 1, 3 and 5 days in vitro. Since these cells are progenitors of immune cells in vertebrate systems (blood cells), they carry out similar functions. For this reason, although they can differ considerably from vertebrates, they have been proved to be very promising sentinels of environmental water qualit
Cohousing for people living with dementia: The Modena experience
AbstractBackgroundSocial isolation, caregiving burden and costs, loss of quality of life related to increasing disability, loss of agency and personhood, are some of the main unmet needs for people with dementia (PwD) and their caregivers. Objective: In order to support people with dementia and their caregivers we implemented a cohousing model. 5 PwD were encouraged to live together. Caregivers were supported in the care according to person centred approach.MethodParticipation in the project (supported by Modena City Council and local Alzheimer association, had been on a voluntary basis. The only exclusion criteria for PwD had been bedridden .Each PwD has his own bedroom with personal belongings and furniture, while the dining and living room are furnished according to prosthetic environment principles. Caregivers turn up in order to both maintain familial environment and reduce global care burden, while formal caregivers, provided by social service and employed by relatives, contribute to PwD care. According to carers expressed needs, voluntaries and an occupational therapist have been engaged to weekly involve PwD in leisure activities and psychosocial intervention. A granted psychologist is available to support Caregivers. A cost analysis, PwD and caregiver quality of life evaluation and caregiving burden were checked. Two control groups of PwD living at home with relatives or family assistant were considered in order to evaluated this cohousing model effectiveness. The first control group was supported by local dementia association. PwD were follow by a memory clinic in cohousing group and in both control groups.ResultA significant cost reduction was found in cohousing group (1879 €/month vs 2502€/month and 2662€/month in control groups). Moreover caregiving burden reduction and an improved PwD and caregivers quality of life were found in cohousing group.ConclusionThis is the first cohousing experience for PwD, in our Country. Relatives improved caregiving experience, reduced financial burden, isolation and time spent for assistance. PwD reduced the risk of institutionalization and improved their quality of life. According to this study results another cohousing experience was open 6 month ago by our community social services
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